Solid-Phase Synthesis of Nickel–Molybdenum Catalysts for Propylene Metathesis under Mechanical Activation

Solid-phase synthesis of aluminum–molybdenum (Al–Mo) and aluminum–nickel–molybdenum (Al–Ni–Mo) model composites as part of propylene metathesis catalysts has been conducted under mechanical activation. The structure of Al–Mo and Al–Ni–Mo model composites has been studied by X-ray diffraction analysis, high-resolution transmission electron microscopy, infrared spectroscopy, and diffuse reflectance electron spectroscopy (DRES). The DRES method has shown the presence of isolated monomeric and oligomeric molybdate compounds in the Al–Ni–Mo model composites. Granular metathesis catalysts have been synthesized by molding the Al–Mo and Al–Ni–Mo model composites with aluminum hydroxide and subsequent calcining. It has been shown that the highest activity in the propylene metathesis reaction is exhibited by an aluminum–molybdenum catalyst containing 2.6 wt % Ni, 13.0 wt % Mo, and 32.7 wt % Al. At a process temperature of 200°C, a pressure of 0.1 MPa, and a propylene feed space velocity of 1 h^–1, in the presence of this catalyst, the propylene conversion achieves 33.7%; this fact makes this catalyst promising for practical applications. At the same time, the weight fraction of ethylene and butenes in the reaction product composition is 17.5 and 71.3%, respectively.